UIAlertControlle的基本用法

 使用UIAlertController需要三步

1、实例化alert:alertControllerWithTitle

2、实例化按钮:actionWithTitle

3、显示alertController:presentViewController

下面是实现上面三步的简单代码

//实例化alert：alertControllerWithTitle

    UIAlertController *alert= [UIAlertController alertControllerWithTitle:@"提示" message:@"请输入账号和密码" preferredStyle:UIAlertControllerStyleAlert];

    //实例化按钮actionWithTitle

    [alert addAction:[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * action) {

        NSLog(@"%@",[alert.textFields.firstObject text]);

    }]];

    //实例化按钮actionWithTitle

    [alert addAction:[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil]];

    //添加文本框

    [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {

        textField.text=self.title;

    }];

    [alert addTextFieldWithConfigurationHandler:^(UITextField * textField) {

        //密文显示

        textField.secureTextEntry=YES;

    }];

    //显示alert

    [self presentViewController:alert animated:YES completion:nil];

这是代码实现的结果